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|Title:||Estimation of breeding values based on first lactation and herd life traits using different animal models in crossbred cattle|
|Publisher:||G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)|
|Keywords:||lactation stage, herds, crossbreds, cattle|
|Abstract:||The present investigation was carried on crossbred cattle maintained at Instructional Dairy farm of G.B. Pant university of Agriculture and Technology, Pantnagar .The data pertaining to 1003 crossbred cattle, progeny of 68 sires which was distributed over a period of 48 years from 1966 to 2010 cows with abnormal and incomplete records were excluded from the study. The following traits were considered for the present study i.e AFC, FLMY, FLP, FDP, FCI, FSP, LTMY, and LTLL. The Least Squares Mean of the traits under study were estimated as 1171.63 ± 21.94 days, 2642.45 ± 89.13 kg., 316.03 ± 5.38 days, 102.83 ± 6.32 days, 418.89 ± 7.23 days, 161.81 ± 9.04 days, 11648 .94 ± 737.87 kg and 1131.91 ± 62.21 days, respectively. The effect due to season of calving was observed to be non- significance on all the first lactation and lifetime traits .The effects due to period of calving were found to have significant influence on first service period ,while highly significant influence on AFC, LTMY and LTLL. However, non-significant influence were observed on FLMY, FLP, FDP and FCI, in contrast different genetic groups were found to have significant effect on AFC, FLMY, FLP and highly significant effect on LTMY, FSP and LTLL, while non- significant effects on FDP and FCI, respectively. Sire effects was highly significant on AFC, LTMY and significant on FLMY, FLP and FCI while non- significant effect on FDP. The heritability estimates for AFC, FLMY, FLP, FDP, FCI, FSP, LTMY and LTLL were observed as 0.24 ± 0.12, 0.34± 0.12, 0.188 ± 0.92.0.448 ± 0.13, 0.607± 0.13, and 0.756± 0.13 respectively. The genetic and phenotypic correlations between first lactation and lifetime traits were ranged from low to high. The estimated breeding values of sires estimated for age at first calving, first lactation milk yield and lifetime lactation length by LSM showed small genetic variance in compare to D, BLUP, REML and DFREML methods. While for FLP, FDP, FCI, FSP and LTMY, BLUP showed small genetic variance in compare to D, LSM, REML methods, therefore LSM and BLUP was considered as the most efficient methods out of all four methods of sire evaluation used in the present study. The product moment correlations ranged from 0.522 (BLUP with LSM) to 0.960 (BLUP with REML) and rank correlations ranged from 0.566 (LSM with BLUP) to 0.956 (BLUP with REML) respectively. The rank of sires for different sire evaluation methods revealed that 4-5% of top sires almost had similar rank for all the methods. These results suggested that for improvement of lifetime productivity of animals, sires should be selected on the basis of their Daughter’s first lactation milk yield.|
|Subject:||Animal Breeding and Genetics|
|Appears in Collections:||Theses|
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